In many applications, it is desired to provide a current protection circuit for an electronic device which is constructed in integrated circuit form. In such case, it is preferable to also provide the protection network in integrated form, so that it can be placed on the same integrated circuit chip. However, known protection circuits require the use of a large number of resistors, and the point at which the circuit operates depends upon the values of one or more resistors. Also, the values of the resistors are critical, and to change the trip point requires changing the resistors, which requires changes in the integrated circuit. Further, to provide an adequate current responsive signal to operate the protection circuit requires the responsive signal to operate the protection circuit requires the use of a resistor which consumes substantial power to provide the voltage drop.
Known protection circuits are also subject to change in the trip point in response to changes in temperature, and/or operating voltage, which change the values of currents in the circuit. This requires the use of additional components to provide compensation, which complicates the circuit and increases the cost.